4589 healthy nulliparous women who were 13 to 21 weeks pregnant were randomly assigned to receive daily treatment with either 2g of elemental calcium or placebo for the remainder of their pregnancies in1992-1995. Calcium supplementation did not significantly reduce the incidence or severity of preeclampsia or delay its onset. In subsequent analysis, the biological samples stored from the trial have been used to determine the associations between angiogenic factors, cell free DNA, thyroid hormone, and other biomarkers on the risk of developing preeclampsia. Other publications have also identified additional risk factors and consequences of preeclampsia with few investigations regarding gestational diabetes. Dr. Richard Levine is the original PI for the study and led numerous investigations using the biospecimens collected from CPEP to investigate the etiology of preeclampsia. After Dr. Levine's passing, Dr. Yeung has been continuing this work. Additional analyses utilizing the study database and specimen repository are being performed. Several biomarkers including the novel biomarker copeptin, which is a cleavage product of preprovassopressin, has been measured. Investigators found that serum copeptin was elevated among women with preeclampsia prior to clinical diagnosis.